176327-44-9Relevant academic research and scientific papers
New approach indole alkaloids based on the intramolecular Pauson-Khand reaction
Perez-Serrano, Leticia,Dominguez, Gema,Perez-Castells, Javier
, p. 5413 - 5418 (2004)
The synthesis of indoles bearing alkenyl and alkynyl moieties in different positions of the nucleus is described. These compounds are used as substrates for the intermolecular Pauson-Khand reaction leading to tetracyclic cyclopentenones with formation of additional five- to seven-membered rings. Products are related to alkaloids such as mitosenes, clausines, ergotamines, or apogeissochizines.
Intramolecular Homolytic Substitution Enabled by Photoredox Catalysis: Sulfur, Phosphorus, and Silicon Heterocycle Synthesis from Aryl Halides
Garrido-Castro, Alberto F.,Salaverri, Noelia,Maestro, M. Carmen,Alemán, José
supporting information, p. 5295 - 5300 (2019/07/03)
Aryl radical generation and manipulation constitutes a long-standing challenge in organic synthesis. Photocatalytic single-electron reduction of aryl halides has been established as a premier activation pathway to reach these intermediates. The current st
Synthetic and Mechanistic Investigation of an Oxime Ether Electrocyclization Approach to Heteroaromatic Boronic Acid Derivatives
Mora-Radó, Helena,Sotorríos, Lia,Ball-Jones, Matthew P.,Bialy, Laurent,Czechtizky, Werngard,Méndez, María,Gómez-Bengoa, Enrique,Harrity, Joseph P. A.
supporting information, p. 9530 - 9534 (2018/07/14)
A range of functionalized heteroaromatic boronic acid derivatives are readily accessed by a diboration/6π-electrocyclization sequence. This study revealed the surprising observation that there is a direct relationship between oxime ether stereochemistry and reactivity towards electrocyclization. Specifically, E-oxime ethers are found to be significantly more reactive than their Z-counterparts (stereochemistry relative to azatriene scaffold). In contrast, the configuration at the azatriene alkene terminus has little impact on reaction rates. Computational analysis offers a rationale for this observation; a Nlone pair→C=C π* orbital interaction lowers the energy of the transition state in the electrocyclization of E-oxime ethers. Finally, unreactive Z-oxime ethers can be converted to the corresponding heterocyclic products by a photolytically promoted E→Z isomerization and electrocyclization sequence.
Rapid generation of privileged substructure-based compound libraries with structural diversity and drug-likeness
Zhang, Lei,Zheng, Mingyue,Zhao, Fei,Zhai, Yun,Liu, Hong
, p. 184 - 191 (2014/05/06)
A library of privileged-substructure-based, heterocyclic compounds was constructed by a sequence of Ugi four-component reactions incorporating the indole motif and microwave-assisted cyclizations in branched pathways. Cheminformatic analysis confirmed that the library exhibited a high degree of structural diversity and good drug-likeness.
Three-step one-pot synthesis of 1,4-dihydropyrazolo[4,3-b]indoles using copper catalysis
Liu, Hong,Liu, Hailong,Zhang, Lei,Zhao, Fei
, p. 1047 - 1052 (2014/03/21)
A convenient three-step one-pot copper-catalysed method has been developed for the preparation of pyrazolo[4,3-b]indoles, new indole-based compounds with potential biological activity. Treatment of various hydrazines, including alkyl hydrazines, with indole-2-carbaldehydes generated the corresponding products in moderate to good yields without protection of the indole N-1 moiety. In addition, LiOH was used as a base in the copper-catalysed coupling reaction. Microwave heating was used to accelerate the iodination of indoles and the C-N bond formation. Diversely substituted pyrazolo[4,3-b]indoles, based on a new indole-containing skeleton, were prepared in a three-step one-pot procedure from unprotected indole-2-carbaldehydes and various hydrazines. LiOH was used as an alternative base in the copper-catalysed protocol. Copyright
Three-Step One-Pot Synthesis of 1,4-Dihydropyrazolo[4,3-b]indoles Using Copper Catalysis
Liu, Hailong,Zhang, Lei,Zhao, Fei,Liu, Hong
, p. 1047 - 1052 (2015/10/05)
A convenient three-step one-pot copper-catalysed method has been developed for the preparation of pyrazolo[4,3-b]indoles, new indole-based compounds with potential biological activity. Treatment of various hydrazines, including alkyl hydrazines, with indole-2-carbaldehydes generated the corresponding products in moderate to good yields without protection of the indole N-1 moiety. In addition, LiOH was used as a base in the copper-catalysed coupling reaction. Microwave heating was used to accelerate the iodination of indoles and the C-N bond formation. Diversely substituted pyrazolo[4,3-b]indoles, based on a new indole-containing skeleton, were prepared in a three-step one-pot procedure from unprotected indole-2-carbaldehydes and various hydrazines. LiOH was used as an alternative base in the copper-catalysed protocol.
Total Syntheses of Carazostatin, Hyellazule, and Carbazoquinocins B-F
Choshi, Tominari,Sada, Takuya,Fujimoto, Hiroyuki,Nagayama, Chizu,Sugino, Eiichi,Hibino, Satoshi
, p. 2535 - 2543 (2007/10/03)
Total syntheses of carazostatin (1), hyellazole (2a), and carbazoquinocins B-F (3b-f) have been completed. The cross-coupling reaction between 3-iodoindole 8 and vinylstannane 11b gave the 3-alkenylindole 7. Treatment of 7 with ethynylmagnesium bromide, followed by etherification of the resulting alcohol 12 with MOMCl, yielded the 3-alkenyl-2-propargylindole 6. The compound 6 was treated with t-BuOK in t-BuOH at 90°C to obtain the desired carbazoles 4 together with the N-deprotected carbazole 13 through an allene-mediated electrocyclic reaction. The carbazole 13a, derived from 4a or 4c, was converted into the triflate 24 in two steps. The triflate 24 was subjected to the Suzuki cross-coupling reaction with either 9-heptyl-9-BBN or phenylboronic acid in the presence of a palladium catalyst to produce the 1-heptylcarbazole 25a and the 1-phenylcarbazole 25b. Cleavage of the ether bond of 25a yielded carazostatin (1). Cleavage of the ether bond of 25b followed by O-methylation gave hyellazole (2a). Oxidation of carazostatin (1) with benzene seleninic anhydride afforded carbazoquinocin C (3c). In a similar way, carbazoquinocins B and D-F (3b,d-f) were synthesized, respectively.
Synthesis of new tetracyclic oxazolocarbazoles as functionalized precursors to antioxidative agents, antiostatins and carbazoquinocins
Choshi, Tominari,Fujimoto, Hiroyuki,Sugino, Eiichi,Hibino, Satoshi
, p. 1847 - 1854 (2007/10/03)
New tetracyclic oxazolo[4,5-c]carbazole and oxazolo[5,4-c]carbazole ring systems as functionalized precursors to antioxidative antiostatins (A1-4 and B2-5) and carbazoquinocins (A-F) were synthesized.
